JP2009291830A - Powder molding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a structure where, particularly, application is made easy by simplification, and flexibility to the change of a design or the like is excellent. <P>SOLUTION: The powder molding device 1 is provided with: a split die 2; a split die holder 3 having a holding hole 7a into which the split die 2 is slidably inserted; and upper and lower punches 4, 5, and constituted so that raw material powder is packed into a cavity C partitioned by a die hole formed at the split die 2 and the lower punch 4 or by them and a core rod 6 is compressed by the relative movement of the upper and lower punches 4, 5, wherein the split die 2 is elevated via a supporting plate 15, and further, the die holder 3 includes a relief part 7b which is provided at the upper side of the inner circumference of the holding hole 7a and comes in non-contact with the outer circumference of the split die 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a powder molding apparatus that compresses a raw material powder into a predetermined shape, and in particular to prevent the occurrence of cracks and scratches on the surface of a molded body due to friction during extrusion after the powder is compressed by a split die configuration. The present invention relates to a powder forming apparatus.

12 (a) and 12 (b) show a powder molding apparatus disclosed in Patent Document 1. FIG. This device is characterized by a split die 14 that is divided into three in the radial direction, a die holder 18 that holds the split die 14 in a closed state and a state in which the split die 14 can be expanded, and the split die 14 is raised and expanded. A die base 12 that switches to a state in which the cutting can be performed, an upper punch 20 and a lower punch 15, and sintering filled in a cavity C defined by a die hole and a lower punch formed with the divided die 14 closed. After the powder H is compressed by the relative movement of the die holder 18 and the upper and lower punches (in this example, the lowering of the upper punch 20), the molded body is pushed out above the split die with the split die 14 in a state where the split die 14 can be expanded. . Another feature is that the suction passage 18m provided so as to cover the divided portion (the boundary between the die portions) of the divided die 14 and the passage 18m provided in the die holder 18 communicate with the passage 18m. It has a passage 18y and a pressure fluctuation means (not shown) that makes the inside of the passage a negative pressure, and allows the powder that has entered the gap between the split dies to be removed through the passage and the pressure fluctuation means.
Japanese Patent No. 3433683

  In the powder molding apparatus having the above-described split die configuration, the powder filled in the cavity is compressed by the relative movement of the die holder and the upper and lower punches, and then the molded body is pushed out above the split die in a state where the split die can be expanded. Therefore, it is possible to efficiently prevent the occurrence of cracks and scratches on the surface of the molded body due to friction during extrusion. However, in this device structure, even if the passage and pressure fluctuation means are omitted, the die is tapered because the outer periphery is tapered or longer than the die holder, so that the cost of manufacturing the die is high, and the versatility to change the design of the molded body shape. And die accuracy is difficult to maintain. Accordingly, an object of the present invention is to provide a structure having excellent versatility with respect to design changes and the like by making it easy to implement particularly by simplification in a powder molding apparatus having a split die configuration.

  In order to achieve the above object, the invention of claim 1 comprises a split die divided in the radial direction, a die holder having a holding hole through which the split die is slidably inserted, and an upper and lower punch. The raw powder filled in the cavity defined by the die hole formed by the split die and the lower punch or the core rod disposed in the die hole is compressed by the relative movement of the upper and lower punches. In the powder molding apparatus, the split die is moved up and down via a support plate, and the die holder is provided so as to open to the upper end surface on the inner peripheral upper side of the holding hole and is not in contact with the outer periphery of the split die It has a relief part.

  In the present invention described above, “compress by the relative motion of the upper and lower punches” includes any one of the one-pressing method, the double-pressing method, the floating die method, and the withdrawal method as the compression method, that is, all known compression methods. Meaning. For this reason, as a compression method, an appropriate method is employable, without being restrict | limited to the method shown to each form.

Further, the present invention is more preferably embodied as follows.
(A) In claim 1, the relief portion is provided in a recessed shape from the upper surface of the die holder, and the recessed lower end is located above the lowest end position of the upper punch when the powder is compressed. The configuration is set (claim 2).
(A) In claim 1 or 2, the escape portion is covered with a cover attached to the upper surface of the die holder (claim 3).
(C) In any one of claims 1 to 3, the die portions are connected to each other via a large-diameter portion and a small-diameter portion that are overlapped with each other in the radial direction (claim 4).

  In the invention of claim 1, as a powder molding apparatus having a divided die configuration, the divided die and the lower punch are both raised in the die-cutting step after the pressurizing step, and as shown in FIG. When the die part constraining the molded body in the die hole reaches the relief portion, the molded body is released from the clamping force caused by the holding hole and becomes a non-clamping mode. Is pushed out of the holding hole of the die holder with a reduced frictional force. That is, in this powder molding apparatus, after compressing the powder, as a structure for preventing cracks and scratches on the surface of the molded body due to friction during extrusion of the molded body, the split die is raised and lowered through the support plate, Since the die holder is provided on the inner circumference upper side of the holding hole and has a relief portion that is not in contact with the outer circumference of the split die, it is simple and excellent in that it is easy to implement.

  In the invention of claim 2, the relief portion is recessed from the upper surface of the die holder, and the height of the recessed lower end is set so as not to impair the compressibility in the pressurizing step, and the molded body is efficiently used in the die cutting step. Makes it possible to realize a simple die cutting operation.

  In the invention of claim 3, for example, in the powder filling step, the powder can be filled into the cavity without falling into the escape portion due to the presence of the cover, whereby the conventional powder supply device (feeder) can be used as it is.

  In the invention of claim 4, since the die parts constituting the split die are connected via the large diameter part and the small diameter part that are overlapped in the radial direction, the powder enters the connection part between the die parts. Even if it does, it will be possible to eliminate the possibility of protruding or falling from the connecting portion to the holding hole side.

  The first embodiment shown in FIGS. 1 to 6 and the second embodiment shown in FIGS. 7 to 11 to which the present invention is applied will be described below. The first form is an example in which the compact (green compact) is cylindrical, and the second form is an example in which the compact (compact) is columnar. In each embodiment, a press drive mechanism is omitted, but a known mechanism such as a hydraulic press is appropriately used.

(First Form) This powder molding apparatus 1 includes a split die 2, a die holder 3 for holding the split die 2, an upper punch 4 and a lower punch 5, and a core rod 6 disposed at the center of the split die 2. The raw material powder H filled in the cavity C defined by the divided die 2 and the lower punch 5 and the core rod 6 is compressed by the relative movement of the die holder 3 and the upper and lower punches 4 and 5. The contrivance points are, in particular, a configuration in which the divided die 2 is moved up and down via the divided die support plate 15, and the die holder 3 is provided with respect to the main body 7 in the divided die holding hole 7a and the clearance provided above the inner periphery of the holding hole 7a. It is the structure which has the part 7b.

  Here, the press structure of the powder molding apparatus 1 includes a rod support plate 10 that holds the core rod 6 from the bottom to the top, a lower punch support plate 13 that holds the lower punch 5 so as to be movable up and down, A split holder support plate 15 that holds the split holder 7 so as to be movable up and down, and an upper punch support plate 17 that holds the upper punch 4 so as to be lifted up and down are provided. Further, the rod support plate 10 and the die holder 3 are connected by a plurality of guide rods 11. The lower punch support plate 13 and the divided holder support plate 15 are assembled in a skewered state via corresponding through holes with respect to the respective guide rods 11, and are arranged in a horizontal state.

  In other words, the upper punch 4 is a cylindrical example and is fixedly supported by the upper punch presser plate 18 with respect to the upper punch support plate 17 and can be lifted and lowered through the upper punch support plate 17 as in the conventional case. . The divided die 2 is fixedly supported by the die presser 16 with respect to the divided die support plate 15 and can be raised and lowered by a predetermined dimension via a divided die support plate 15 by a hydraulic device (not shown). The lower punch 5 is cylindrical and fixedly supported by the lower punch support plate 13 with respect to the lower punch support plate 13, and protrudes to the through hole provided in the divided die support plate 15 and the inner diameter side of the divided die 2. The lower punch support plate 15 can be moved up and down by a hydraulic device (not shown) or the like. The core rod 6 is fixedly supported by the rod presser 12 with respect to the rod support plate 10, and protrudes from the through hole provided in the lower punch support plate 13 and the inner diameter of the lower punch 6 toward the split die 2 side.

  The divided die 2 is an example of four equal parts as shown in FIGS. 1 and 2, and is divided into die portions 2A to 2D in the radial direction around the cylindrical shape. Each die part 2A-2D is a substantially L shape, and if a perpendicular | vertical part is arrange | positioned in the holding hole 7a by the side of a main body, it will be in the restraint state which die parts closely_contact | adhere without gap, and forms a die hole. In addition, it is preferable that the division | segmentation die | dye 2 is divided | segmented into 3 or more in order to obtain the non-restraining state mentioned later uniformly.

  That is, the die holder side main body 7 has a substantially central holding hole 7a for supporting the divided die 2, an escape portion 7b provided on the inner peripheral upper side of the holding hole 7a and not contacting the outer periphery of the divided die 2, and an outer periphery. And a ring-shaped die outer peripheral portion 8 integrated with each other. The holding hole 7a has a hole diameter that allows the vertical portion of the divided die 2 to slide without a gap, and the die portions 2A to 2D are inserted from below. The escape portion 7b is provided so as to open to the upper end surface on the inner peripheral upper side of the holding hole 7a. In other words, the escape portion 7 b is provided in a hollow shape that gradually decreases in diameter as it goes downward from the upper end surface of the main body 7. Further, the lower end of the escape portion 7b is set to be the same as or slightly above the lowest end position of the upper punch 4 when the powder H is compressed as shown in FIG.

  The die outer peripheral portion 8 is integrated by attaching the coupling member 19 straddling between the two in a state where the main body 7 is engaged with the inner periphery of the main body 7. The die outer peripheral portion 8 and the main body 7 constitute a die table. Note that the upper end of the guide rod 11 is connected to the outer periphery 8 of the die.

  Moreover, the cover 30 which covers the upper surface of the die holder 3, and the escape 7 part b is attached to the above powder shaping | molding apparatus 1 as needed, as shown with the dashed-dotted line of FIG. The cover 30 is a thin cover body that has a through-hole through which the divided die 2 is inserted and is attached to the upper surface of the die holder 3. The raw material powder uses a powder supply device (conventional feeder) in the powder filling step. Thus, when the cavity C is filled, the escape portion 7 is prevented from entering. However, since this cover 30 can be omitted by devising the powder supply device, it is omitted except for FIG. 1 and FIG.

  Next, a powder compression method using the above powder molding apparatus 1 will be described. As this powder compression method, a powder filling process for filling the cavity C with the powder H, a pressurizing process for compressing the powder H, and a die cutting process for extruding the molded body are performed.

  1 and 2 show a powder filling process. In this step, the divided die 2 is disposed at the lower limit position via the divided die support plate 15, and the lower punch 5 is disposed at the lower limit position via the lower punch support plate 13, and the die hole formed by the divided die 2, A cavity C is defined by the punch 5 and the core rod 6. The cavity C is filled with powder H via a powder supply device (not shown).

  FIG. 3 shows the pressurizing process. In this step, the upper punch 4 is lowered through the upper punch support plate 17 and inserted into the die hole of the divided die 2, and the lower punch 5 is raised through the lower punch support plate 13, The powder H in the cavity C is compressed. Reference numeral H1 denotes a molded body in which the powder H is pressure-molded in this way.

  4 to 6 show a die cutting process. In this step, first, as shown in FIG. 4, the upper punch 4 is raised through the upper punch support plate 17 and pulled out from the die hole of the divided die 2. Further, the divided die 2 is raised to the upper limit position via the divided die support plate 15 and simultaneously the lower punch 5 is raised by a predetermined distance via the lower punch support plate 13. Then, in this structure, the dividing die 2 and the lower punch 5 are raised until the lower end of the molded body H1 is substantially the same as or slightly higher than the escape portion 7b. The split die 2 is engaged with the holding hole 7a because the split die 2 is divided into die parts 2A to 2D, and the part in the escape part 7b and the part projecting upward therefrom are in an unconstrained state. It becomes easier to displace radially outward or release the load radially outward than the part (restrained part). FIG. 5 schematically shows such an operation with arrows.

  From this state, the lower punch 5 is raised to the upper limit position of FIG. 6 via the lower punch support plate 15, and then the divided die 2 is lowered to the original lower limit position. Then, the molded body H1 in the die hole of the split die 2 is pushed up by the lower punch 5 and extracted from the die hole. In this extraction process, the molded body H1 has a die hole inner periphery and a core rod 6 because the part of the split die 2 that is in the relief part 7b and the part that protrudes upward from the part are in an unconstrained state. It is pushed up by the lower punch 5 with almost no frictional force with the outer periphery, thereby reliably preventing the occurrence of cracks and scratches on the surface due to friction during extrusion.

  Next, in the state of FIG. 6, the molded body H 1 is transferred from the die table including the die outer peripheral portion 9, the main body 8, and the divided die 2 to a target location. In order to return to the state of FIG. 1, the lower punch 5 is lowered to the lower limit position via the lower punch support plate 13, and then the powder H is filled as described above.

(Second Mode) In this mode, FIG. 7 corresponds to FIG. 1, FIG. 8 corresponds to FIG. 2, FIG. 9 corresponds to FIG. 3, FIG. 10 corresponds to FIG. It corresponds to. This powder molding apparatus 1A is an example of molding a columnar molded body H2, and as shown in FIGS. 7 and 8, the divided die 20, the die holder 3 holding the divided die 20, the upper punch 4A and the lower punch 5A. The raw material powder H filled in the die hole formed by the divided die 20 and the cavity C1 defined by the lower punch 4A is compressed by relative movement of the die holder 3 and the upper and lower punches 4A and 5A. The main part is the same as the above-described configuration, in which the divided die 20 is moved up and down via the divided die support plate 15, the die holder 3 is located above the main body 7 on the inner periphery of the divided die holding hole 7 a and the holding hole 7 a. It is the structure which has the provided escape part 7b.

  The press structure of the powder molding apparatus 1A is different in that the rod support plate becomes the base support plate 10 because there is no core rod 6 of the above configuration, but the other configurations are substantially the same as the above configuration. That is, the upper punch 4 </ b> A is fixedly supported by the upper punch presser 18 with respect to the upper punch support plate 17, and can be moved up and down via the upper punch support plate 17. The divided die 20 is fixedly supported by a die presser 16 with respect to the divided die support plate 15 and can be raised and lowered by a predetermined dimension via a divided die support plate 15 by a hydraulic device (not shown). The lower punch 5A is fixedly supported by the lower punch holder 14 with respect to the lower punch support plate 13, and is protruded to the through hole provided in the divided die support plate 15 and the inner diameter side of the divided die 20, so that the lower punch support plate 15 can be moved up and down by a hydraulic device (not shown) or the like.

  The split die 20 is an example of four equal parts as shown in FIG. 8, and is divided into die parts 20A to 20D along the periphery. Each die part 2A-2D is a substantially L shape, and if a perpendicular | vertical part is arrange | positioned in the holding hole 7a by the side of a main body, it will be in the restraint state which die parts closely_contact | adhere without gap, and forms a die hole. In this case, each die part 2A to 2D has a shape on both sides, one side (right side in the example of FIG. 8) is a small diameter part 20a with a single outer wall of the outer surface, and the other side (left side in the example of FIG. 8) is an inner surface. Are formed in a large-diameter portion 20b in which one step is cut out and set so as to be overlapped in the radial direction. This is because the powder H is connected to the die portions, specifically, the large diameter portion 20b of the die portion 20A and the small diameter portion 20a of the die portion 20B, and the large diameter portion 20b of the die portion 20B and the small diameter of the die portion 20C. Portion 20a, large-diameter portion 20b of die portion 20B, small-diameter portion 20a of die portion 20C, even if the joint portion of large-diameter portion 20b of die portion 20C and small-diameter portion 20a of die portion 20D enters the connecting portion. This is effective in eliminating the possibility of protruding or falling from the holding hole 7a.

  The die holder side main body 7 has a substantially central holding hole 7a for supporting the divided die 20, an escape portion 7b that is provided on the inner peripheral upper side of the holding hole 7a and is not in contact with the outer periphery of the divided die 20, and is integrated with the outer periphery. And a ring-shaped die outer peripheral portion 8 which is formed. The holding hole 7a has a hole diameter that allows the vertical portion of the divided die 2 to slide without a gap, and the die portions 2A to 2D are inserted from below. The escape portion 7 b is provided in a hollow shape that gradually becomes smaller in diameter as it goes downward from the upper surface of the main body 7. Moreover, it is preferable that the lower end of the escape portion 7b is set to be the same as or slightly above the lowest end position of the upper punch 4 when the powder H is compressed as shown in FIG.

  The die outer peripheral portion 8 is integrated by attaching the coupling member 19 straddling between the two in a state where the main body 7 is engaged with the inner periphery of the main body 7. The die outer peripheral portion 8 and the main body 7 constitute a die table. Note that the upper end of the guide rod 11 is connected to the outer periphery 8 of the die.

  Next, a powder compression method using the above powder molding apparatus 1A will be described. Even in this powder compression method, a powder filling process for filling the cavity C1 with the powder H, a pressure process for compressing the powder H, and a die-cutting process for extruding the molded body are performed. In the powder filling step, the divided die 20 is disposed at the lower limit position via the divided die support plate 15, and the lower punch 5A is disposed at the lower limit position via the lower punch support plate 13, respectively. The die hole of the divided die 20 and the lower punch 5A are disposed. And the cavity C1 is defined. The cavity C1 is filled with the powder H in the same manner as in the above embodiment.

  FIG. 9 shows a pressurizing process. In this step, the upper punch 4A is lowered via the upper punch support plate 17 and inserted into the die hole of the split die 20, and the lower punch 5A is raised via the lower punch support plate 13, The powder H in the cavity C1 is compressed. The symbol H2 is a molded body in which the powder H is pressure-molded in this way.

  10 and 11 show the die cutting process. In this step, first, as shown in FIG. 10, the upper punch 4 </ b> A is raised through the upper punch support plate 17 and pulled out from the die hole of the divided die 20. Further, at the same time when the divided die 20 is raised to the upper limit position via the divided die support plate 15, the lower punch 5 </ b> A is raised by a predetermined distance via the lower punch support plate 13. In this structure, the divided die 20 and the lower punch 5A are raised until the lower end of the molded body H2 is substantially the same as or slightly higher than the escape portion 7b. The split die 20 is divided into die parts 20A to 20D, and a part in the escape part 7b and a part protruding upward from the part are engaged with the holding hole 7a because the part is not restrained ( Compared to the constrained portion), it becomes easier to displace radially outward or release the load radially outward.

  From this state, the lower punch 5A is raised to the upper limit position of FIG. 11 via the lower punch support plate 15, and then the divided die 20 is lowered to the original lower limit position. Then, the molded body H2 in the die hole of the split die 20 is pushed up by the lower punch 5A and extracted from the die hole. In this extraction process, the molded body H2 is in a state where the portion of the split die 20 in the escape portion 7b and the portion protruding upward are in an unconstrained state. It is pushed up by the lower punch 5A with almost no frictional force, so that it is possible to reliably prevent the occurrence of cracks and scratches on the surface due to friction during extrusion. These are the same as the above forms.

  In addition, the powder molding apparatus of this invention should just be substantially provided with the structure specified by a claim, and a detail can be further changed and developed with reference to each form.

It is a longitudinal cross-sectional view which shows the powder shaping | molding apparatus of a 1st form in a powder filling state. (A) is a top view of the apparatus main body of FIG. 1, (b) is the sectional view on the AA line of FIG. It is a longitudinal cross-sectional view which shows the apparatus of FIG. 1 in the state which compressed the powder. FIG. 4 is a longitudinal sectional view showing an initial stage of a die-cutting process in which the above-mentioned apparatus is lifted by a predetermined distance from the state shown in FIG. FIG. 5 is a schematic plan view showing the operation of the apparatus main body in the state of FIG. 4. It is the longitudinal cross-sectional view which raised the molded object from the state of FIG. It is a longitudinal cross-sectional view which shows the powder shaping | molding apparatus of a 2nd form corresponding to FIG. (A) is a top view of the apparatus main body of FIG. 7, (b) is the BB sectional drawing of FIG. It is a longitudinal cross-sectional view which shows the apparatus of a 2nd form corresponding to FIG. It is a longitudinal cross-sectional view which shows the apparatus of a 2nd form corresponding to FIG. It is a longitudinal cross-sectional view which shows the apparatus of a 2nd form corresponding to FIG. (A), (b) is the longitudinal cross-sectional view and BB sectional drawing of the powder shaping | molding apparatus disclosed by patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1A ... Powder shaping | molding apparatus 2,20 ... Divided die (2A-2D is a die part, 20A-20D is a die part)
3 ... Die holder (7 is a main body, 7a is a holding hole, 7b is a relief portion, 8 is a die outer peripheral portion)
4, 4A ... Upper punch 5, 5A ... Lower punch 6 ... Core rod 13 ... Lower punch support plate 15 ... Split die support plate 17 ... Upper punch support plate 30 ... Cover C, C1 ... Cavity H ... Raw material powder H1, H2 ... Molding Body (green compact)

Claims (4)

A die hole formed by the divided die, the lower die, and a die holder having a divided die that is divided in the radial direction, a die holder having a holding hole through which the divided die is slidably inserted, and a lower punch In the powder molding apparatus for compressing the raw powder filled in the cavity defined by the punch or the core rod disposed in the die hole by the relative movement of the upper and lower punches,
The split die is moved up and down via a support plate, and the die holder is provided on the inner periphery upper side of the holding hole so as to open to the upper end surface, and has a relief portion that is not in contact with the outer periphery of the split die. A powder molding apparatus.   The relief portion is provided in a recessed shape from the upper surface of the die holder, and the recessed lower end is set to be above the lowest end position of the upper punch when the powder is compressed. The powder molding apparatus according to claim 1 or 2.   3. The powder molding apparatus according to claim 1, wherein the escape portion is covered with a cover attached to an upper surface of the die holder.   The powder molding apparatus according to any one of claims 1 to 3, wherein the die parts are connected to each other through a large diameter part and a small diameter part that are overlapped in the radial direction.

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